Merge pull request swiftlang#58 from frankeh/thmgmt_inform

inform libpwq thread manager before semaphore wait

Author: MadCoder

libpwq

@@ -383,6 +383,7 @@ _dispatch_semaphore_wait_slow(dispatch_semaphore_t dsema,
 			uint64_t nsec = _dispatch_timeout(timeout);
 			_timeout.tv_sec = (typeof(_timeout.tv_sec))(nsec / NSEC_PER_SEC);
 			_timeout.tv_nsec = (typeof(_timeout.tv_nsec))(nsec % NSEC_PER_SEC);
+			pthread_workqueue_signal_np();
 			ret = slowpath(_dispatch_futex_wait(&dsema->dsema_futex, &_timeout));
 		} while (ret == false && errno == EINTR);
 
@@ -430,6 +431,7 @@ _dispatch_semaphore_wait_slow(dispatch_semaphore_t dsema,
 		DISPATCH_SEMAPHORE_VERIFY_RET(ret);
 #elif USE_FUTEX_SEM
 		do {
+			pthread_workqueue_signal_np();
 			ret = _dispatch_futex_wait(&dsema->dsema_futex, NULL);
 		} while (ret == false && errno == EINTR);
 		DISPATCH_SEMAPHORE_VERIFY_RET(ret);
@@ -648,6 +650,7 @@ _dispatch_group_wait_slow(dispatch_semaphore_t dsema, dispatch_time_t timeout)
 			uint64_t nsec = _dispatch_timeout(timeout);
 			_timeout.tv_sec = (typeof(_timeout.tv_sec))(nsec / NSEC_PER_SEC);
 			_timeout.tv_nsec = (typeof(_timeout.tv_nsec))(nsec % NSEC_PER_SEC);
+			pthread_workqueue_signal_np();
 			ret = slowpath(_dispatch_futex_wait(&dsema->dsema_futex, &_timeout));
 		} while (ret == false && errno == EINTR);
 
@@ -695,6 +698,7 @@ _dispatch_group_wait_slow(dispatch_semaphore_t dsema, dispatch_time_t timeout)
 		DISPATCH_SEMAPHORE_VERIFY_RET(ret);
 #elif USE_FUTEX_SEM
 		do {
+			pthread_workqueue_signal_np();
 			ret = _dispatch_futex_wait(&dsema->dsema_futex, NULL);
 		} while (ret == false && errno == EINTR);
 		DISPATCH_SEMAPHORE_VERIFY_RET(ret);